ASPIRE: A Study Promoting critical Illness Recovery in the Elderly Project Abstract: Older people have a higher risk of developing a critical illness requiring invasive mechanical ventilation than younger people. Additionally, muscle wasting, which occurs quickly and progresses rapidly in all patients who are critically ill and on mechanical ventilation, is more severe in older adults. This results in long-term physical impairments, particularly in older survivors of critical illness. ICU rehabilitation, when administered early, has been shown to be effective at attenuating the degree of physical function impairment in survivors. However, there are barriers to the provision of early ICU rehabilitation, including delirium and coma. Additionally, older patients have been routinely excluded from critical care trials even though they make up the majority of the critically ill population. We recently performed a pilot feasibility trial of a novel, early ICU rehabilitation protocol in older adults utilizing an in-bed cycle ergometer. The in-bed cycle ergometer allowed for ICU rehabilitation to start at a particularly early point in the ICU course when muscle wasting begins, and allowed delivery of rehabilitation even when patients were comatose or delirious. We hypothesize that the novel, early ICU rehabilitation protocol using an in-bed cycle ergometer will improve functional outcomes in older survivors of critical illness. As such, the specific aims of the proposal are to evaluate the effect of the early ICU rehabilitation intervention on 1) physical function (as measured by the SPPB at ICU discharge), 2) muscle mass (as measured by ultrasound at ICU discharge), and 3) quality of life (measured with the SF-36 at 6 months post-discharge). This will be the first randomized controlled trial to test this novel early ICU rehabilitation intervention in older patients. This project and period of training with the GEMSSTAR award will be critical in my transition to becoming a clinical trialist with a focus on improving older adults' physical function following critical illness.